Brake mechanism



' March 16, 1937.

J. SNFED BRAKE MEQHANISM Original Filed March 15, 1928- 2 Sheets- Sheetl INVENTOR Jo JNEED BY g 7/ ATTORNEY March 16, 1937. 'J. SNEED Re.20,299

BRAKE MECHANI-SM' Original Filed March 15, 1928 2 Sheets-Sheet 2INVENTOR Jar/N 5N3 V ATTORNEY Reissued Mar. '16, 1937 UNITED STATESPATENT OFFICE 20,299 BRAKE MECHANISM Original No. 1,857,481, dated May10, 1932, Serial No. 261,761, March 15, 1928.

Application for reissue April 19, 1934, Serial N 0. 721,383

24 Claims.

This invention relates to brakes and is illustrated as the type of brakesuitable for use on a motor vehicle. The invention has to doparticularly with means for causing engagement between the brake shoeand the brake drum.

In internal expanding brakes it has been common practice to expand theshoe or other friction device by means of a cam positioned be tweenadjacent ends of the shoe, and it has been found expedient in manyinstances to permit the cam to float bodily with the ends of the shoe tomaintain an expanding force while the brake is being applied. Oneskilled in the art knows that this result has been accomplished innumerous instances either by allowing the cam shaft to shift or bypermitting the cam to shift with relation to the cam shaft. Floatingtoggles connected to adjacent ends of brake shoes have been used. Whilethere has been found merit in both types of devices, it is among theobjects of my invention to provide a spreading means which may bemounted on a fixed axis and which will move either end of the frictionelement to any desired distance while the other end remains sta- 5tionary or even moves in the same direction.

Other objects involve providing adjustment between the expanding deviceand the ends of the shoe. Another object is to provide connectionsbetween the ends of the shoe and the expansion device.

Other objects will appear from the following detailed description of theembodiment of my invention illustrated in the accompanying drawings. Theessential characteristics are summarized in the claims.

In the drawings Fig. 1 illustrates an elevation of the brake assembly;Fig. 2 is a section taken along the lines 2-2 of Fig. 1; Fig. 3 is asection taken along the lines 3-3 of Fig. 1; Fig. 4 is a section takenalong the lines 44 of Fig. 1, and Fig. 5 is a section taken along theline 5-5 of Fig. 1.

Referring to the drawings, a back plate or apron A is carried by theaxle or knuckle not shown and carries a bracket B (see also Fig. 2)which in turn carries an anchor pin P. J ournalled in the bracket is ashaft S to which an arm R is fixed and through which arm the shaft S maybe rotated by brake operating means not shown. The usual rotatable brakedrum D is intended to be fixed to a wheel, not shown. In this embodimentof my invention, I illustrate a substantially annular brake shoe Inwhich may be channeled in cross section in part having inwardlyextending side flanges H (see Fig. 5). I prefer that the side flanges bedeepestat the ends of the shoe and decrease in depth toward themid-portion to points I2. The mid portion I3 of the shoe is formed in aflat curved lining supporting part of relatively great flexibility. Thedegree of flexibility of the channeled portions of the shoe may berelatively small but they may have within themselves a degree offlexibility depending upon the depth of the channel. The ends of theshoes having inwardly extending side flanges which are cut away to formarcuate bearing portions, engage the anchor pin as at M. Thus, wheneither end of the shoe is forced away from the anchor depending on thedirection of drum rotation, the other end may swing about the anchor pininto engagement with the drum, but because of the relatively slightflexibility of the end portions of the shoes, the wrapping effect of thebrake will be limited, and grabbing will be avoided. In other words, themaximum unit pressure between the lining of the shoe can be kept withindesired limits and the area of greater pressure can be extended from apoint spaced away from the anchor around through the channeled portionof the shoe. Suitable brake lining L may be carried by the shoe. Mainretractor springs [6 are provided as shown and an auxiliary retractorspring I1 is used to draw one portion of the shoe against an adjustablestop member l8.

Located in a position complementary to the stop member I8, I provide ananti-rattling device l9, illustrated in greater detail in Fig. 4. Thedevice may comprise a member 20 extending in part through the apron andengaging a piece of the shoe 2| which has been pressed inwardly. Anadjustable bolt with a spring 22 acting through the member 20 urges theshoe against a raised portion of the apron 23.

Carried by the side flanges of the shoe, adjacent the ends thereof arepins 30 and 30a which may be similar to each other and which are engagedby the spreading device as at 3| and 3| a. These pins may be freelyrotatable if desired, but for the sake of simplicity of illustration, Ihave shown them as being provided with hexagonal heads 32. The pins arerestrained from lateral movement by suitable means such as cotter pinsas shown. The side flanges of the shoes have aligned hexagonal openingsas at 33 (see also Fig. 1) in which the hexagonal heads of the ends arefitted. To effect adjustment between the expansion device and ends ofthe shoe, the relative position of the heads of the pins may be changedin the openings in the side flanges of the shoes so that the center ofeither or both of the pins may be moved toward or away from the end ofthe shoe. As shown in Figs. 1 and 3, the pins 30 and 3011 are in theposition most remote from the ends of the shoe and either or both of thepins may be moved nearer their respective shoe ends by changing theposition of the heads 32 in the openings 33. While I have illustratedhexagonal heads for the pins, it is of course to be understood that anypolyangular head or eccentric head might be used in this connection.

Referring particularly to Figs. 1, 2 and 3, the expansion device may bedescribed as follows: The shaft S has been referred to as beingjournalled in the bracket B and rotatable by brake operating connectionsthrough the arm R. Formed integrally and coaxially with the shaft S is acylindrical member 40, which I have illustrated as being ofsubstantially greater diameter than the shaft. Freely journalled on thecylinder 40 is a member 4| which preferably encircles the cylindricalmember 40 and has an upwardly extending arm 42. The arm 42 extendsbetween the anchor pin P and the pin 30 (see also Fig. 3) and contactswith the pin 30 as at 3|, as mentioned above. The member 40 in additionto having the upwardly extending arm 42 has a pair of outwardlyextending lugs 43 and 4311 which are spaced apart 'as at 44 andpositioned generally diametrically opposite the arm 42. Referringparticularly to Figs. 1 and 2, another member 5| is carried by thecylinder and this member is pivotally mounted eccentricallyof the axisof the cylinder by such means as a pin 45. The member 5| also has anupwardly extending arm 52 which passes between the anchor and the pin30a (see also Fig. 3) and contacts with the pins 300. as at 3| a. Themember 5| has in addition to the upwardly extending arm 52, a downwardlyextending arm 53, which may lie over the end face of the cylinder andpass between the lugs 43 and 43a of the member 42 in the space indicatedat 44.

The operation of the expanding device is as follows: Assuming therotation of the drum to be counter-clockwise, which, according to theillustration of Fig. 1, follows from the usual forward movement of thevehicle, it will be desirable to obtain a servo effect, to move the endof the shoe indicated at into engagement with the drum and to retain onthe anchor the end 10 of the shoe. To effect this, the shaft S and thecylinder 40 are turned in a counter-clockwise direction, as viewed inFig. 1 so that the pin 45 is carried counter-clockwise.Counter-clockwise movement of the pin 45 tends to shift the member 5|bodily to the left as viewed in Fig. 1, exerting a pressure on both thepin 30 and the lug 43a. The pressure on the pin 30a tends tomove the end60 of the shoe into engagement with the'drum, while pressure on the lug43a tends to rotate the member 4| in a clockwise direction so that thearm 42 of the member 4| exerts a pressure on the pin 30. The relation ofthe forces exerted is a matter of proportion and design, but in theembodiment shown herewith and in the instance now described, therotation of the drum tends to carry the shoe in a counter-clockwisedirection to force the end 10 of the shoe upon the anchor and to holdthe pin 30 in fixed relation relative to the anchor pin so that the lug43a is not moved and that all of the motion of the pin 45 is transmittedto movement of the pin 30a.

If the rotation of the drum be clockwise by reason of the vehicle movingin a reverse direction then the operation of the expanding device issimilar, but different in the following regards: The rotation of theshaft S is the same and the pin 45 moves in a counter-clockwisedirection from its position of rest, but in this instance the end 60 ofthe shoe is forced against the anchor by the rotation of the drum sothat regardless of the initial and preliminary motion, the pin 30 isheld in a fixed position with relation to the anchor pin. Thiscounter-clockwise movement of the pin 45 is transmitted to clockwisemovement of the lug 4311 about the cylinder 40 which causes the arm 42of the member 4| to move to the right as viewed in Fig. 1, forcing theend 10 of the shoe into engagement with the drum.

It will be seen from the foregoing that the shoe expanding deviceillustrated and described gives a full floating spreading action in thateither end of the shoe may be moved from the anchor while the other endremains in engagement therewith. As the lining wears, compensation maybe had by repositioning either or both of the pins 30 and 300. asdescribed above. The simplicity of the device and ruggedness of thestructure assure long life and dependable service, and while I haveillustrated and described a preferred embodiment of my invention, I donot care to be limited in the scope thereof other than by the claimsappended hereto.

I claim:

1. Shoe expanding mechanism for a brake, comprising a rotatablecylinder, a member pivotally and eccentrically mounted on said cylinder,a second member pivotally and concentrically mounted on said cylinder,each of said members having arms extending away from the cylinder andengaging the ends of the shoe, said members engaging each other wherebyrotation of said cylinder spreads said arms.

2. Shoe expanding mechanism for a brake, comprising a rotatablecylindrical part, a mem-- ber carried by said part on a pivot whose axisis above and eccentric to the axis of said part, a second memberpivotally mounted to rotate about the cylindrical part, each of saidmembers having arms extending above and away from the cylinder andengaging the ends of the shoe, said members also engaging each otherbelow the axis of the cylindrical part whereby rotation of said cylinderspreads said arms.

3. Shoe expanding mechanism for a brake, including a member rotatable ona fixed axis, a second member rotatable about the same axis, and a thirdmember rotating about an axis spaced from the first axis and engagingthe second member at a point beyond the first axis and remote from thesecond axis whereby rotation of the first member causes the movement inopposite directions of parts of the second and third members. a

4. Shoe expanding mechanism for a brake, including a member rotatable ona fixed axis, a second member rotatable about the same axis, and a thirdmember rotating about an axis spaced from and above the first axis andengaging the second member at a point beyond and below the first axisand remote from the second axis whereby rotation of the first membercauses rotational movement of the second and third members.

5. A brake having an anchor pin, friction means having ends anchorableagainst said pin, a rotatable shaft, a member concentrically mounted onsaid shaft for moving one end of said friction means away from saidanchor pin, and a member eccentrically mounted on the said shaft andengaging the other end'of said friction means and said concentricallymounted member.

6. A brake having an anchor pin, friction means having ends anchorableagainst said pin, means for moving one end of said friction means awayfrom said anchor pin including a member rotatable about a fixed axis, asecond member eccentrically mounted on the first member and engaging theend of said friction means, and means engaging both said members and theother end of said friction means.

7. A brake including an anchor, friction means having ends engaging saidanchor, and means for spreading the ends of said friction meansincluding a rotatable shaft parallel to the anchor pin and adjacentthereto, a member carried by the shaft and rotatable concentrictherewith, and a second member carried by the shaft and rotatableeccentrically thereof, and engaging the first member.

8. A brake including an anchor, friction means having ends engaging saidanchor, and means for spreading the ends of said friction meansincluding a rotatable shaft parallel to the anchor pin and adjacentthereto and having an enlarged cylindrical part, a member carried by thecylindrical part and rotatable concentric therewith, and a second memberpivotally mounted on the end of said cylindrical part and rotatableconcentrically thereof and engaging the first member.

9. Shoe spreading means for a brake includ ing a part rotatable about afixed axis, a member having an arm engageable with one end of the shoeand freely encompassing said part and having a lug extending parallelwith the axis of the part and beyond the face thereof, and a secondmember pivotally mounted on the face of the cylinder at a point removedfrom the axis of the part and having an arm engageable with the otherend of the shoe and having a second arm engaging said lug.

10. Shoe spreading means for a brake including a shaft rotatable about afixed axis, a member having an arm engageable with one end of the shoeand freely encompassing the shaft and having a lug lying below andextending parallel with the axis of the shaft beyond the end thereof,and a second member pivotally mounted on the end of the shaft above theaxis thereof at a point removed from the axis of the cylinder and havingan arm engageable with the other end of the shoe and having a second armengaging said lug.

11. In a brake, the combination of an anchor pin, a shoe having endsengaging said pin, adjustable bearing members associated with the endsof said shoes and means for spreading the ends of said shoes engagingsaid members and comprising a shaft rotatable about a fixed axis andhaving two members each engageable with one of said first named membersand with one another, one of said last named members mountedconcentrically of the shaft and the other mounted eccentrically thereof.

12. In a brake, the combination of an anchor pin, a shoe having endsengaging said pin, adjustable bearing members associated with the endsof said shoes and means for spreading the ends of said shoes engagingsaid members and comprising a shaft rotatable about a fixed axis andhaving two members each engageable with one of said first named members,one of said last named members mounted concentrically of the ,13. Shoeexpanding mechanism for a brake comprising a shaft rotatable about afixed axis, means concentrically rotatable about said axis, and engagingone end of the shoe, and means eccentrically mounted about said axis andengaging the other end of the shoe and the concentrically rotatablemeans.

14. In'a brake, an apron, a drum, an anchor, a brake shoe havingseparable ends and a lining supporting flange and a. radial web, saidweb terminating at points intermediate the ends of said shoe to givedifferent characteristics of rigidity and flexibility thereto, and ashoe expanding mechanism for said band comprising a shaft rotatableabout a fixed axis, means eccentrically mounted about said axis andengaging one of the ends of said shoe.

15. In a brake, the combination of a brake drum, an apron, a brake shoehaving separable ends, a peripheral Web and a radial web, said radialweb being cut away in that portion of the shoe intermediate the ends toimpart varying degrees of flexibility and rigidity to.the shoe, and afloating device for spreading said shoe comprising a rotatable shaft, amember rotatable with said shaft, means operatively connecting saidshaft with said shoe ends to separate said ends, said forces beingunequal as applied to said ends whereby one of said ends will be movedbefore the other.

16. A brake comprising, in combination, friction means having partsseparable to apply the brake, a rotatable shaft adacent said parts, andmembers carried by the shaft and moved in opposite directions by saidshaft into contact with said parts to apply the brake, said membersbeing relatively movable and being balanced against each other tobalance the forces acting on said parts.

1'7. A brake comprising, in combination, friction means having partsseparable to apply-the brake, a rotatable shaft adjacent said parts, andinterengaging pivoted devices carried by the shaft and moved in oppositedirections by said shaft into contact with said parts to apply thebrake.

18. A brake-applying device adapted for direct operative engagement withthe friction means of a brake, and comprising, in combination, anangularly-movable operating part, and thrust parts independently pivotedon the operating part and the thrusts of which are balanced against eachother.

19. A brake applying device adapted for direct operative engagement withthe friction means of a brake, and comprising, in combination, anangularly-movable operating part, and thrust parts independently pivotedon the operating part and which are in direct balancing engagement witheach other.

20. A brake cam device constructed and arranged to be mounted within abrake and comprising, in combination, a shaft, a head turned by saidshaft, and a pair of interengaging thrust members independently pivotedon said head and arranged to operate the friction parts of the brake.

21. An expanding device for an internal expanding brake comprising amember rotatable about a fixed axis and a pair of parts pivotallymounted on said member and connected to interact with each other, eachof said parts engaging one end of the friction device whereby rotationof said member spreads the ends of the device from each other.

22. The combination. of a brake friction means having movable ends,anchorage means therefor, and means for forcing said ends intoengagement with a brake drum including a rotatable member and a pair ofarms pivotally mounted on. said member, each of said arms engaging oneof said ends and said arms engaging each other whereby rotation of saidmember causes said arms to exert opposed forces on said ends.

23. An expanding device for a full floating internal expanding brakecomprising a member rotatable about a fixed axis and a pair of partspivotally mounted on said member and connected to interact with eachother, each of said parts engaging one end of the friction devicewhereby rotation of said member spreads the ends of the device from eachother even if one of the ends is held stationary.

24. The combination of a full floating brake shoe, means for anchoringeither end of said shoe, and means for forcing either end of said shoeaway from its anchorage and into engagement with the brake drumincluding a rotatable member and a pair of arms pivotallymounted on saidmember, each of said arms engaging one end of the shoe and said armsbeing connected with each other whereby rotation of said member causesboth of said arms to exert opposed forces on the ends of the shoe andmove one of the ends of the shoe into engagement with the drum, theother end of the shoe imposing the braking torque on the anchor.

JOHN SNEED.

